Mechanic says adding oil is normal...every 2 to 3 weeks? on 2002 BMW 525i

I have a 2002 525 wagon. It has 95K miles. the check engine oil light comes on every 2 to 3 weeks, at which time I have to add a quart of oil. Is this normal or am I heading toward a small fortune fix? I am just about at wits end with all this spending and want out if this is the case. Please help. mechanic says this is normal for high milage beamers. Thoughts???

Asked by for the 2002 BMW 525i
The PCV Valve Part #11617501566 is a possible cause but NO GARRANTY that’s it I would replace it and see what happens there not that expensive from Sunrise Automotive 714-8983100